Method and apparatus for preventing excessive power drain from an implantable device

ABSTRACT

A method and apparatus are provided for controlling interrogation of an implantable device such as a pacemaker, an implantable cardioverter, or a defibrillator utilizing an external device in a home environment. The method controls how frequently a patient can retrieve status information from the implantable device based on a time period elapsed since a last interrogation and a power level of a battery.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.11/551,661, filed Oct. 20, 2006, now U.S. Pat. No. 7,720,545 titled“Method and Apparatus for Preventing Excessive Power Drain from anImplantable Device”.

FIELD OF THE INVENTION

Embodiments of the present invention pertain generally to implantablemedical devices, such as cardiac pacemakers and implantable cardioverterdefibrillators, and more particularly pertain to methods and apparatusthat prevent excessive electrical power drain while exchanginginformation with devices outside the body.

BACKGROUND OF THE INVENTION

In the United States, it is estimated that approximately five millionpeople have congestive heart failure (“CHF”). CHF is a life threateningcondition that is managed by treating patients with drugs or implantablemedical devices such as pacemakers and implantable cardioverterdefibrillators (“ICD”). The information obtained through monitoring canbe used to diagnose and treat a patient's condition.

Current ICDs and pacemakers have the ability to non-invasivelycommunicate a patient's physical data and programmable parameters with adevice such as an external programmer. The programmer is used tointerrogate or program the ICD or pacemaker using a wireless, radiofrequency telemetry link. Typically, a physician or medical professionalutilizes the programmer, while the patient is in the medical office, toaccess data stored by the ICD or pacemaker, check and adjust onprogrammed parameters and the like. The programmer can also be used toinstruct the ICD or pacemaker to execute desired functions, such asmonitoring, stimulating, and storing diagnostic or other data.Conventional programmers in the marketplace allow numerous differentparameters to be programmed. The ability to exchange data via a wirelesslink also permits the health care provider to reprogram or reconfigurethe implantable device as required from time to time due to changes inthe patient's condition. Recently, implantable devices have beenproposed that allow a patient to operate certain types of home-basedprogrammers to interrogate the implantable device in the privacy of thepatient's own home. Heretofore, patients have been able to use thehome-based programmers at any time to interrogate the implantabledevice.

However, home-based programmers present the opportunity for undueinterrogation of the implantable device, and thus excessive drain on abattery of the implantable device. A power supply, typically aspecialized battery, is housed within the implantable device to providethe electrical energy required for operation over an extended length oftime. One difficulty is the efficient use of electrical energy. Thelifetime of the battery depends on the power demands of the implantabledevice. For instance, implantable devices that require high speed andlong range telemetry require greater battery power. ICDs also require abattery to operate at low current drains for long periods of time andsimultaneously provide high current pulses. For example, the normallifetime of a battery may be five years. To provide the longest batterylife, it is desirable to reduce the power consumption required for thevarious functions of the implantable device. Because replacing a batteryrequires surgery, it is preferable that the battery last as long aspossible.

Most implantable devices are configured to support interrogation bymedically trained professionals in a medical office. Most implantabledevices do not have the capability of allowing the patient to performthe interrogation at home, and therefore, there is not as great aconcern with the drainage of battery power. However, as implantabledevices are manufactured to include the feature of allowing a patient tointerrogate the implantable device, additional power concerns emerge.Specifically, if a patient does not judiciously interrogate the device,for example if the patient checks the implantable device every fewminutes, a heavy power drain on the battery will result. This, in turn,will affect the ability of the implantable device to communicaterequired patient data as well as affect the operation of the implantabledevice. Depletion of battery power will potentially lead to earlyfailure of the implantable device and require the battery to be replacedmore frequently.

A need remains for an improved implantable device including electricalcircuitry and programmable features to limit the number ofinterrogations performed by a patient in a home environment in order toextend battery life.

SUMMARY

In accordance with one embodiment of the present invention, a method isprovided for controlling interrogation of an implantable device. Themethod includes accepting, at the external device, a request forinformation from an implantable device after verifying a thresholdperiod of time has elapsed since the last request for information.

In accordance with a further aspect of the invention, an externaldevice, such as a programmer, requests information from an implantabledevice, which includes a monitoring module, a memory module, and aninput/output (“I/O”) module having a telemetry unit. The monitoringmodule records the last request for information from the patient'sexternal device to the memory module and verifies a threshold period oftime has elapsed since the last request for information. The telemetryunit establishes a wireless communication link with the external deviceand transmits the requested information stored within the memory modulebased on the amount of time elapsed since the last request forinformation.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings, which are not necessarily drawn to scale, like numeralsdescribe substantially similar components throughout the several views.Like numerals having different letter suffixes represent differentinstances of substantially similar components. The drawings illustrategenerally, by way of example, but not by way of limitation, variousembodiments discussed in the present document.

FIG. 1 illustrates an implantable device formed in accordance with oneembodiment of the present invention that remotely communicates with anexternal programmer.

FIG. 2 illustrates a block diagram of an implantable device incommunication with an external programmer utilized in accordance with anembodiment of the present invention.

FIG. 3 illustrates a block diagram of an external device incommunication with an implantable device, as shown in FIG. 2, utilizedin accordance with an embodiment of the present invention.

FIG. 4 illustrates a flow chart for a process to control interrogationof an implantable device based on the time lapse since the lastinterrogation stored in the patient's external device in accordance withan embodiment of the present invention.

FIG. 5 illustrates a flow chart for a process to control interrogationof an implantable device based on the time lapse since the lastinterrogation stored in the implantable device in accordance with anembodiment of the present invention.

DETAILED DESCRIPTION

In the following detailed description, reference is made to theaccompanying drawings which form a part hereof, and in which is shown byway of illustration specific embodiments in which the present inventionmay be practiced. These embodiments, which are also referred to hereinas “examples,” are described in sufficient detail to enable thoseskilled in the art to practice the invention, and it is to be understoodthat the various embodiments of the invention may be combined, or thatother embodiments may be utilized and that structural, logical andelectrical changes may be made without departing from the scope of thepresent invention. For example, embodiments may be used with apacemaker, a cardioverter, a defibrillator, and the like. The followingdetailed description is, therefore, not to be taken in a limiting sense,and the scope of the present invention is defined by the appended claimsand their equivalents.

In this document, the terms “a” or “an” are used, as is common in patentdocuments, to include one or more than one. In this document, the term“or” is used to refer to a nonexclusive or, unless otherwise indicated.

FIG. 1 illustrates a programmable cardiac system 10 that includes animplantable device 12 in communication with a clinician's externaldevice 14 and a patient's external device 15 via a communication link 16that is controlled in accordance with an embodiment of the presentinvention. The implantable device 12 includes a connector 20 that isjoined to a plurality of leads 22. Physiological information is detectedover the leads 22 that are located with or near a heart 24 at either anatrium, a ventricle or both. The physiological information is providedthrough leads 22 via connector 20 to the implantable device 12. Theimplantable device 12 monitors the heart 24 of a patient and detectswhen the patient is having a post-myocardial infarct, a “silent”myocardial infarct, a myocardial infarct, an ischemia, a heart block, anarrhythmia, a fibrillation, or a congestive heart failure.

Additionally, the implantable device 12 provides an electricalstimulation through the leads 22 based on the physiological informationdetected. For example, stimulation may be provided when the intrinsicheartbeat is insufficient, when depolarization is not being conductedthrough the heart 24, when the heart rate is too slow to maintainadequate blood from to the body and the like. In addition, implantabledevice 12 detects electrical characteristics of heart 24 subject to apreventative pacing scheme such as bi-ventricular, right ventricular,left ventricular, left atrial, right atrial, and bi-atrial pacing. Bymonitoring the excitability of cardiac tissue and its response todifferent pacing schemes, the implantable device 12 is able to provide aphysician with information as to the patient's physiological condition,e.g., whether it has improved or is progressing towards cardiac failure.

A physician can utilize the external device 14 to access informationstored within the implanted device 12. The external device 14 may beimplemented as a programmer in accordance with an embodiment of thepresent invention. Information is accessed from the implantable device12 after the communication link 16 is established between theimplantable device 12 and the external device 14.

The external device 14 permits a physician to examine the operation ofthe implantable device 12. During an office visit, the physician has theability to review physiological data and programmed parameters of theimplantable device 12, as well as to adjust these parameters through theexternal device 14 depending on the physiological condition of thepatient. Some parameters that a physician may be interested inprogramming include fibrillation detection rate, tachycardia detectionrate, ventricular fibrillation detection rate, ventricular tachycardiadetection rate, and the like. Setting a defibrillation detection ratetoo low may result in an unnecessary defibrillation that is both painfuland potentially damaging to the heart. On the other hand, setting adetection rate too high may cause the required electrical shock not tobe applied in a timely manner to a fibrillating heart and the patientmay die.

In home-based applications, the patient is limited to certain functionsthat he/she can access through the external device 15 while at home.Thus, the patient should be allowed to access a restricted set ofinformation, such as the patient's overall cardiac physiologicalcondition, whether to consult a physician or not, and the status of theimplantable device, e.g., battery power condition.

FIG. 2 illustrates a block diagram of a portion of implantable device12. The implantable device 12 may be a cardiac pacemaker, an implantablecardioverter defibrillator (“ICD”), a defibrillator, or an ICD coupledwith a pacemaker implemented in accordance with an embodiment of thepresent invention. The implantable device 12 includes a processor module30, a data/control bus module 32, a sensing module 34, a monitoringmodule 36, a memory module 38, an Input/Output (“I/O”) module 40, and abattery 42. It is understood that data/control bus module 32, sensingmodule 34, monitoring module 36 and I/O module 40 are conceptual blocks,not necessarily separate hardware and may be implemented in software bythe processor module 30.

Processor module 30 typically includes a microprocessor, amicrocomputer, or equivalent control circuitry for processingphysiological characteristics of the heart 24. The processor module 30may further include RAM or ROM memory, logic and timing circuitry, statemachine circuitry, and I/O circuitry. Typically, the processor module 30includes the ability to process or monitor data as controlled by aprogram code stored in a designated block of memory. Data/control busmodule 32 represents a hardware or software interface between thevarious functional modules of the implantable device 12.

Sensing module 34 includes a signal conversion module 44. The sensingmodule 34 receives physiology signals from the leads 22, such as adepolarization wave as it spreads through the cardiac tissue andmeasures the timing, direction of propagation, and point of initiationof successive depolarization waves. The depolarization may be a resultof an inherent cardiac cycle or in response to a cardiac pacing event,such as pacing the heart utilizing bi-ventricular pacing, rightventricular pacing, left ventricular pacing, left atrial pacing, rightatrial pacing or bi-atrial pacing. The signal conversion module 44typically includes an analog-to-digital (“A/D”) converter (not shown)and receives raw analog signals that are voltages that result from thechange in ionic concentrations of sodium and calcium through the cardiactissue that occur during depolarization. The signal conversion module 44converts the raw analog signals to a plurality of digital signals. Thedigital signals are transferred over the data/control bus module 32 andstored in the memory module 38.

The monitoring module 36 analyzes the digital physiology signals fromthe signal conversion module 44 and identifies desired physiologiccharacteristics. For example, the monitoring module 36 may identifyarrhythmias, trends in cardiac behavior, and the like. The monitoringmodule 36 determines the programmed state of the implantable device 12and determines the remaining battery power, which is stored as batterycondition 48. As previously mentioned the implantable device 12 can beprogrammed by a physician to operate in a specific mode, e.g., detectventricular fibrillation and deliver an associated therapy. Themonitoring module 36 verifies and records that the implantable device 12is in the correct programmed state (e.g., not a harmful state) and theamount of time within each state. If the monitoring module 36 detects aharmful state, it will report a warning to the external device 14 or tothe patient's external device 15 through the I/O module 40. Themonitoring module 36 also collects timing information that includes atime the data is transmitted, a date the data is transmitted, a numberof total interrogations performed, and the date and time of eachinterrogation request. The monitoring module 36 also monitors operationof the implantable device 12 in connection with receipt and transmissionof information and parameters by and from the telemetry unit 52.

In addition, each time a request to interrogate the implantable device12 is made by the external device 15, the monitoring module 36 checks onthe status of the battery 42 and records the battery condition 48 in thememory module 38. As the power of the battery decreases, the monitoringmodule 36 extends the time period required to accept a newinterrogation. If the battery power is below a threshold level, themonitoring module 36 will prevent further responses to patient'sexternal device 15. The battery power level depends on the type and sizeof battery 42 utilized by the implantable device 12. Typical batteries42 include zinc-mercury batteries, nickel-cadmium batteries, nuclearbatteries, fuel cells, lithium iodine batteries and the like. Themonitoring module 36 also checks on the frequency of interrogations. Ifa specified threshold time period has not lapsed when an interrogationis requested, the monitoring module 36 prevents the interrogation frombeing answered.

The memory module 38 includes blocks of memory allocated to storeprogrammable parameters 46, a communications log 47, a battery condition48, and physiological characteristics 50. The blocks of memory may beROM, PROM, EPROM, EEPROM, RAM, SRAM, DRAM, DDRAM, EDO, SDRAM, Flash,MRAM, FRAM, EEPROM, EAPROM and the like. The communications log 47records data related to past communications to and from the implantabledevice 12. For example, the communications log 47 may include a time atwhich each incoming transmission is received, a time at which eachoutgoing transmission was transmitted, a length of each outgoingtransmission, a nature or type associated with incoming and outgoingtransmissions and an identification of the implantable device 12, aswell as an identification of the type of device requesting information,e.g., the physician's external device 14 or the patient's externaldevice 15. The nature or type of the transmission and length thereof maybe of interest to estimate an amount of battery power used in connectionwith the transmission by the implantable device 12.

The programmable parameters 46 may include a tachycardia detection rate,a fibrillation detection rate, a ventricular tachycardia rate, aventricular fibrillation detection rate, a bradycardia rate, stabilityalgorithm settings, onset algorithm settings, specific therapies foreach cardiac zone, a duration of therapy required for each cardiac zoneand the like. The battery condition 48 may include a low power batterystatus, a battery internal resistance, a number of charge/dischargecycles, battery age, and a remaining battery charge. The physiologicalcharacteristics 50 may include a series of digitized data signalsdetected by the leads 22 over time and/or a patient's heart rate, anelectrical activation pattern of the heart, a strength of contraction ofheart muscle, and an amount of fluid in the lungs. Furthermore, thephysiological characteristics 50 may also include a possible currentcondition of the patient, such as a patient's tachycardia rate, apatient's bradycardia rate, a patient's fibrillation rate, and apatient's arrhythmia rate or whether the patient is suffering from amyocardial infarction, a post-myocardial infarction, a “silent”myocardial infarction, an ischemia, an arrhythmia, a heart block, afibrillation, or a congestive heart failure. These physiologicalcharacteristics 50 may be transmitted as physiologic information by atelemetry unit 52 to the physician's external devices 14 or to thepatient's external device 15.

Input/Output (“I/O”) module 40 includes a telemetry unit 52. Thetelemetry unit 52 enables the implantable device 12 to download data tothe physician's external device 14 when a patient is at the physician'soffice or to the patient's external device 15 when the patient is athome via a wireless link 16. The telemetry unit 52 interfaces withprocessor module 30 and monitoring module 36 to determine whether toperform an interrogation. A patient that does not exercise discretionwhen making requests for interrogation via the external device 15 canwear down the battery 42. A low battery condition may be defined as atleast 10% of the maximum battery power level, or as a power level thatleads to imminent battery power failure. The lifetime of the battery 42depends on the power demands of the implantable device 12 as well as thefrequency of interrogations. For instance, the implantable device 12 mayrequire the battery 42 to operate at low current drains for long periodsof time and simultaneously provide high current pulses. To provide thelongest battery life, it is desirable to reduce the power consumptionrequired for the various functions of the implantable device 12. Bylimiting a patient's ability to interrogate the implantable device 12,battery power is conserved.

FIG. 3 illustrates a block diagram of a patient's external device 15 inaccordance with an embodiment of this invention. The patient's externaldevice 15 includes a processor module 60, an address/data/control busmodule 62, a data/memory module 64, a program memory module 66, a userinterface module 68, a telemetry module 70 and a battery 72.Address/data/control bus module 62, data/memory module 64, programmemory module 66, user interface module 68 and telemetry module 70represent hardware blocks that may partially or totally implemented onthe same semiconductor die.

Processor module 60 typically includes a microprocessor, amicrocomputer, or equivalent control circuitry for processing a requestto interrogate an implantable medical device 12. The processor module 60may further include RAM or ROM memory, logic and timing circuitry, statemachine circuitry, and I/O circuitry. Typically, the processor module 60includes the ability to process or monitor data as controlled by aprogram code stored in program module 66.

Address/data/control bus module 62 represents a hardware interfacebetween the various functional modules of the patient's external device15.

The data memory module 64 includes blocks of memory allocated to storephysiological information, timing information that includes a time thedata is transmitted, a date the data is transmitted, a number of totalinterrogations performed, and the date and time of each interrogationrequest, and a battery condition.

The program memory module 66 includes blocks of memory allocated tostore a program code that instructs processor 60 regarding the operationof external device 15. For instance, the program code may includeinstructions on how the user may interface with the external device 15,what information the user may be allowed to access, and what formatmessages will be provided to the user (e.g., visual, textual, auditory).

The blocks of memory may be ROM, PROM, EPROM, EEPROM, RAM, SRAM, DRAM,DDRAM, EDO, SDRAM, Flash, MRAM, FRAM, EEPROM, EAPROM and the like.

The user interface 68 accepts commands from the user and displays therequested interrogation information, and the telemetry module 70interfaces with the implantable device 12 over a wireless link. Further,the telemetry unit 70 is commanded by processor module 60 to communicatewith the implantable device 12. Patient's external device 15 alsoincludes a battery 72.

In one embodiment of the present invention, the processor module 60monitors each time a request is made by the user utilizing externaldevice 15 to interrogate the implantable medical device 12. Theprocessing module 60 checks data memory 64 for the last time the usermade a request. If a specified threshold time period has not lapsed whenan interrogation is requested, the processor module 60 prevents theinterrogation from being performed. If the specified threshold timeperiod has lapsed, the processor 60 performs an interrogation ofimplantable device 15 via telemetry module 70. The processor module 60monitors the receipt and transmission of information and parameters byand from the telemetry unit 70 to ensure communication is successful.The processor module 60 then logs the interrogation in data memory 64.For example, the processor 60 may, for example, log a time at which eachincoming transmission is received, a time at which each outgoingtransmission was transmitted, a length of each outgoing transmission, anature or type associated with incoming and outgoing transmissions andan identification of the implantable device 12. The processor 60utilizes user interface 68 to show/display the requested information tothe user.

FIG. 4 illustrates a process to control the interrogation of theimplantable device 12 utilizing the patient's external device 15 inaccordance with at least one embodiment of the present invention. At100, the patient utilizes the external device 15 to make a request tointerrogate the implantable medical device 12. At 102, the externaldevice 15 compares the time elapsed from the last request forinterrogation with a value for the current time threshold. The timethreshold is the amount of time that must elapse before an interrogationis permitted. If the time elapsed from the last interrogation is lessthan the required time threshold, external device 15 denies the requestand no interrogation to implantable device 12 is initiated. The patientmust wait until the time threshold has elapsed before making anotherrequest for interrogation.

The time threshold is dynamically modified by the device that keepsrecord of the time elapsed since last interrogation (e.g., eitherpatient's external device 15 or implantable device 12) based on thebattery power level reported by implantable device 12. Table 1 shows anembodiment of how the time threshold can be modified based onimplantable device 12's battery power level.

TABLE 1 BATTERY POWER STATUS TIME THRESHOLD FULL Thr1 MID Thr2 > Thr1LOW Thr3 > Thr2 CRITICAL Thr4 > Thr3For instance, when the battery power level is “full” (e.g. battery isfully charged) the time threshold is initially at a value of Thr1. Inone embodiment, Thr1 may allow the patient to perform an interrogationutilizing the patient's external device 15 once per hour. In anotherembodiment, Thr1 may allow the patient to perform an interrogation onceper day. As the battery power decreases to a “mid” level (e.g. 50% powercharge), processor module 30 will assign a new time threshold value,Thr2, where Thr2 will have a greater value than Thr1. Thus, Thr2 willrestrict the frequency of interrogation in comparison to Thr1. In oneembodiment, Thr2 may allow the patient to perform an interrogationutilizing the patient's external device 15 up to once a week. In anotherembodiment, Thr2 may allow an interrogation to be performed once amonth. As the battery power level decreases to a “low” level (e.g. lessthan 50%), processor module 30 will assign Thr3 as the time thresholdvalue. The value or Thr3 will be greater than Thr2. In one embodiment,Thr3 may allow a patient to interrogate the implantable medical device12 once every three months. In an alternative embodiment, Thr3 may allowa patient to perform an interrogation once every six months. As thebattery power level drops to a “critical” level (e.g. less than 10%),process module 30 will assign Thr4 as the time threshold value. At the“critical” level, the maximum time period allowable is assigned to atime threshold value. In one embodiment, Thr4 will not allow the patientto perform any interrogations of implantable device 12. There can be aplurality of time thresholds. For example, in one embodiment, a timethreshold can be assigned for every 10% drop in battery power (e.g.,100% corresponds to Thr1, 90% corresponds to Thr2, 80% corresponds toThr3, 70% corresponds to Thr4, etc., and at the “critical” level 10%corresponds to Thr10).

If the time elapsed from last interrogation is longer than the requiredtime threshold per 102, then at 104, patient's external device 15 sendsa request for interrogation via a wireless connection to implantabledevice 12. Telemetry unit 52 receives the request for interrogation, andtransfers the request via data bus 32 to monitoring module 36. TheProcess module 30 then retrieves the required information from thememory module 38 and has the I/O module 40 transfer the requestedinformation to the patient's external device 15.

At 106, I/O module 40 monitors the process of interrogation and thestatus of the wireless connection. If the wireless connection fails orthe communication between the external device 15 and the implantablemedical device 12 fails for any reason during the interrogation process,monitoring module 36 will end the process. No log will be kept of theinterrogation, and the patient must request another interrogation.

At 106, if the interrogation proceeds successfully, then at 108 a log ofthe interrogation (e.g. time and date of interrogation) will be made andstored on patient's external device 15.

FIG. 5 illustrates a processing sequence where the time logs of aninterrogation are stored in the implantable device 12 in accordance withan embodiment of this invention. Beginning at 200, the patient controlsexternal device 15 and starts a request to interrogate the implantabledevice 12. For example, in one embodiment, the patient may push a buttonon external device 15 to request an interrogation.

At 202, the patient's external device 15 initiates the interrogation bysending a request via a wireless connection to the implantable device12. In one embodiment, external device 15 may be inductively coupledwith the implantable device 12. The request is received by telemetryunit 52 and the request is transferred along data bus 32 to monitoringmodule 36.

At 204, processor module 30 checks if the time elapsed from the lastinterrogation from external device 15 is longer than the current timethreshold value. If the threshold has not expired, the process will beterminated at 206 and no response will be made. However, if thethreshold value has expired, the process continues. At 208, implantabledevice 12 responds to external device 15 by having processor 30 retrievethe requested information from memory module 38 and transmit theinformation via I/O module 40 to external device 15. At 210, implantabledevice 12 logs the time and date of the interrogation in memory module38.

It is to be understood that the above description is intended to beillustrative, and not restrictive. For example, the above-describedembodiments (and/or aspects thereof) may be used in combination witheach other. In addition, many modifications may be made to adapt aparticular situation or material to the teachings of the inventionwithout departing from its scope. The scope of the invention should,therefore, be determined with reference to the appended claims, alongwith the full scope of equivalents to which such claims are entitled. Inthe appended claims, the terms “including” and “in which” are used asthe plain-English equivalents of the respective terms “comprising” and“wherein.” Moreover, in the following claims, the terms “first,”“second,” and “third,” etc. are used merely as labels, and are notintended to impose numerical requirements on their objects.

1. A system for controlling interrogation of an implantable deviceutilizing an external device, the system comprising: said implantabledevice; a module, in the implantable device, adapted to receive acurrent request for information to be retrieved from the implantabledevice; a monitoring module, in the implantable device, adapted torecord a temporal history of previous interrogations of the implantabledevice, to compare the temporal history of previous interrogations withthe current request for information, and to decide whether to allow theinterrogation process to proceed based on the comparison; and atelemetry unit adapted to establish a wireless communication link withthe external device; wherein the monitoring module is adapted to preventthe interrogation process from proceeding when a period of time elapsedsince a last request for the information is shorter than a thresholdperiod of time.
 2. The system according to claim 1, wherein theinformation requested includes at least one of physiologicalinformation, programmable information, timing information, and a batterycondition.
 3. The system according to claim 1, wherein the informationconstitutes physiological information that includes at least one of aheart rate, an electrical activation pattern of the heart, a strength ofcontraction of heart muscle, an amount of fluid in the lungs, atachycardia rate, a bradycardia rate, a fibrillation rate, and anarrhythmia rate.
 4. The system according to claim 1, wherein theinformation constitutes battery condition that includes at least one ofa low power battery status, a battery internal resistance, a number ofcharge/discharge cycles, battery age, a battery voltage and a remainingbattery charge.
 5. The system according to claim 1, wherein themonitoring module is adapted to prevent the implantable device fromproceeding with the interrogation process when a battery power level isbelow a threshold battery value.
 6. The system according to claim 1,wherein the implantable device constitutes at least one of a pacemaker,an implantable cardioverter defibrillator, and a defibrillator.
 7. Asystem controlling interrogation of an implantable device utilizing anexternal device, the system comprising: said implantable device; amodule, in the implantable device, adapted to receive a current requestfor information to be retrieved from the implantable device; amonitoring module, in the implantable device, adapted to record atemporal history of previous interrogations of the implantable device,to compare the temporal history of previous interrogations with thecurrent request for information, and to decide whether to allow theinterrogation process to proceed based on the comparison; and atelemetry unit adapted to establish a wireless communication link withthe external device; wherein the monitoring module, in the implantabledevice, is further adapted to check the battery condition including thepower level of the battery; and wherein the monitoring module, in theimplantable device, dynamically updates the threshold period of time toa new value based on said power level of a battery within theimplantable device, the threshold period of time used in comparison ofthe temporal history of previous interrogations with the current requestfor information.
 8. A method for controlling interrogation of animplantable device utilizing an external device, the method comprising:receiving a current request for information, at the implantable device,to be retrieved from an implantable device; determining, by theimplantable device, a temporal history of previous interrogations of theimplantable device; comparing, by the implantable device, the temporalhistory of previous interrogations with the current request forinformation and with a threshold period of time that is to elapse beforeaccepting a new request for information; allowing the interrogationprocess to proceed based on the comparing; transmitting information fromthe implantable device to the external device; checking and recording abattery condition; and as the battery condition decreases, extending, atthe implantable device, the threshold period of time that is to elapsebefore accepting a new request for information.
 9. The method accordingto claim 8, wherein the transmitting information includes reading theinformation from a memory location within the implantable device. 10.The method according to claim 8, wherein the information includes atleast one of physiological information, programmable information, andtiming information.
 11. The method according to claim 8, wherein thebattery condition comprises a battery power level and wherein the methodfurther comprises preventing, by the implantable device, transmission ofthe information when the battery power level is less than a thresholdbattery value.
 12. The method according to claim 8, wherein theimplantable device constitutes at least one of a pacemaker, animplantable cardioverter defibrillator, and a defibrillator.
 13. Themethod according to claim 8, further comprising storing, in memory ofthe implantable device, at least one of a time and date of when data istransmitted from the implantable device, a number of totalinterrogations performed, and a time and date of each interrogation. 14.The method according to claim 8, wherein the determining operation isperformed by a monitoring module in the implantable device afterreceiving a request for information from the external device.